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| United States Patent |
5,324,702
|
|
Yoo
, et al.
|
June 28, 1994
|
Catalytic oxidation and oxidative dehydrogenation using
metal-compound-loaded, deboronated hams-1b crystalline borosilicate
molecular sieve compositions
Abstract
Compositions comprising certain metal-containing materials distributed
interactively on a deboronated HAMS-1B crystalline borosilicate molecular
sieve which are useful for catalytically oxidizing or oxidatively
dehydrogenating organic compounds such as alkanes, aromatics, and
alkyl-substituted aromatics are described. Alkanes are oxidatively
dehydrogenated to olefins, and an aromatic compound such as benzene can be
oxidized by nitric and/or nitrous oxide to largely phenol or largely
nitrobenzene depending upon the oxidation temperature. When the compound
is a methylaromatic, oxidation produces an aromatic aldehyde. Alkyl groups
larger than methyl oxidatively dehydrogenate to alkenyl groups. The
compositions can be used in a process to separate p-xylene from a mixture
of its isomers based upon the ability of the compositions, which
preferably comprise a iron molybdenum material interactively distributed
on a deboronated HAMS-1B crystalline borosilicate molecular sieve, to
selectively oxidize the p-xylene to an aldehyde or dialdehyde while not
substantially oxidizing the ortho and metaxylene isomers. Such partially
oxidized mixtures of p-xylene are useful to make TPAA or as feeds to a
water-based, further oxidation to make terephthalic acid. Carbon dioxide
used as a carrier gas with a methylaromatic feed to the oxidation catalyst
is shown to have a beneficial effect on yield and selectivity.
| Inventors:
|
Yoo; Jin S. (Flossmoor, IL);
Kleefisch; Mark S. (Naperville, IL);
Donohue; John A. (Elmhurst, IL)
|
| Assignee:
|
Amoco Corporation (Chicago, IL)
|
| Appl. No.:
|
991113 |
| Filed:
|
December 16, 1992 |
| Current U.S. Class: |
502/204; 502/205; 502/206; 502/207 |
| Intern'l Class: |
B01J 021/00; B01J 037/00 |
| Field of Search: |
502/206,207,204,205
|
References Cited
U.S. Patent Documents
| 4268420 | May., 1981 | Klotz | 502/206.
|
| 4451685 | May., 1984 | Nevitt et al. | 502/206.
|
| 4462971 | Jul., 1984 | Hinnenkamp et al. | 502/206.
|
| 4725570 | Feb., 1988 | Sikkenga et al. | 502/207.
|
Primary Examiner: Dees; Carl F.
Attorney, Agent or Firm: Nemo; Thomas E., Oliver; Wallace L.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No.
07/796,470 filed Nov. 22, 1991 and now abandoned, the specifications and
claims of which are incorporated by reference herein.
Claims
That which is claimed is:
1. A composition comprising a minor amount of a material consisting of a
first component which is a compound of an element selected from the group
consisting of Fe(III), Zn(II), Zr(IV), Nb(V), In(III), Sn(IV), Sb(V),
Ce(III) and Bi(III), and a second component which is a compound of an
element selected from the group consisting of V(V), Mo(VI) and W(VI),
which first and second components are interactively distributed on a major
amount of deboronated HAMS-1B crystalline borosilicate molecular sieve
containing less than about 0.1 weight percent as the element of boron.
2. The composition of claim 1 wherein the total metals in the minor amount
of material is in a range form about 0.5 to about 15 weight percent of the
total weight of the composition.
3. The composition of claim 2 wherein the minor amount of a material
consisting of a first component which is a compound of an element selected
from the group consisting of Fe(III), Zn(II), Sb(V), and Bi(III), and a
second component which is a compound of an element selected from the group
consisting of Mo(VI) and W(VI).
4. The composition of claim 2 wherein the first component is a compound of
Fe(III) and the second component is a compound of Mo(VI), and the minor
amount of iron-molybdenum material having a molybdenum to iron ratio in a
range from about 1.5 to about 2.5 distributed on a major amount of
deboronated HAMS-1B crystalline borosilicate molecular sieve containing
less than about 0.1 weight percent as the element of boron.
5. The composition of claim 2 made by a process comprising:
depositing a volatile iron compound on a HAMS-1B crystalline borosilicate
molecular sieve containing at least about 0.4 weight percent as the
element of boron or a predeboronated HAMS-1B crystalline borosilicate
molecular sieve containing less than about 0.1 weight percent of boron as
the element from the vapor phase to form an iron-containing, deboronated
HAMS-1B crystalline borosilicate molecular sieve;
washing and drying said iron-containing deboronated HAMS-1B crystalline
borosilicate molecular sieve;
depositing a volatile molybdenum compound on said washed and dried
iron-containing deboronated HAMS-1B crystalline borosilicate molecular
sieve from the vapor phase to form an iron-molybdenum-containing
deboronated HAMS-1B crystalline borosilicate molecular sieve; and
heating said iron-molybdenum-containing deboronated HAMS-1B crystalline
borosilicate molecular sieve to form a composition comprising a minor
amount of an iron molybdenum material having a molybdenum to iron ratio
between about 1.5 and about 2.5 distributed on a major amount of
deboronated HAMS-1B crystalline borosilicate molecular sieve containing
less than about 0.1 weight percent as the element of boron.
Description
BACKGROUND OF THE INVENTION
This invention relates to compositions containing a pair of metal compounds
distributed interactively on a deboronated HAMS-1B crystalline
borosilicate molecular sieve (DBH) and a process of using such
compositions as oxidation or oxidative dehydrogenation catalysts. More
particularly, this invention relates to an improved process and
composition for the alkyl group oxidation or oxidative dehydrogenation of
an alkyl-substituted aromatic using a novel metal-compound-containing
composition based upon a deboronated HAMS-1B crystalline borosilicate
molecular sieve. Still more particularly, this invention relates to
improved process for the methyl group oxidation of a methyl-substituted
aromatic, such as p-xylene, to an aromatic mono and/or dialdehyde using a
catalytic amount of a novel composition containing an iron molybdenum
material distributed interactively on a deboronated HAMS-1B crystalline
borosilicate molecular sieve.
U.S. Pat. No. 3,597,485 discloses a process for preparation of
terephthalaldehyde (referred to herein as TPAA) which comprises subjecting
p-xylene to a vapor phase oxidation in the presence of a catalyst mixture
consisting of tungsten and molybdenum compounds.
U.S. Pat. No. 3,845,137 describes a process for preparation of TPAA in
which p-xylene is oxidized in the vapor phase in the presence of a
supported catalyst mixture of oxides of tungsten and molybdenum and at
least a third metal or oxide selected from the group consisting of
calcium, barium, titanium, zirconium, hafnium, thallium, niobium, zinc,
and tin. According to this patent, the three component catalyst
composition processes have improved catalyst life when compared to the
catalyst described in U.S. Pat. No. 3,597,485. However, in both of these
patents the conversion of p-xylene to TPAA is low.
U.S. Pat. No. 4,017,547 describes an improved process for making TPAA which
uses a mixture of molybdenum oxide and silico-tungstic acid in combination
with bismuth oxide. Catalyst lifetime and conversion to TPAA are both said
to be improved over the prior art techniques. Not only is the conversion
of p-xylene to TPAA said to be increased substantially by the use of the
oxide of bismuth, but catalyst life is also said to be improved
considerably, thereby permitting the operation of the oxidation process
for longer periods of time before catalyst regeneration is required.
In an article entitled "Polymer Applications of Some Terephthalaldehyde
Derivatives" in Ind. & Eng. Chem., Prod. Res. Dev. 15 (1) 83-88(1976), the
authors use a tungsten-molybdenum catalyst in a ratio of about 9:1
deposited in an amount of ten percent or less on an alumina support to
oxidize a mixture of air and p-xylene at 475.degree. C. to 575.degree. C.
to a mixture of tolualdehyde (TAL) and TPAA. A 40-60% yield of TPAA with a
minor production of byproducts is reported. The lifetime of the catalyst
however appears to be poor.
Two catalyst properties are of primary importance for the operation of a
continuous oxidation or oxidative dehydrogenation process which converts
alkanes, aromatics or alkyl aromatics on a commercial scale. The first is
yield of the desired oxidation product and the second is catalyst
lifetime.
Now it has been discovered that metal-compound-containing compositions
based on a deboronated HAMS-1B crystalline borosilicate molecular sieve
having the MFI crystal structure can be very selective in oxidation and
oxidative dehydrogenation reactions while having a long lifetime. For
example, the alkyl group oxidation of an alkyl-substituted aromatic in the
presence of a catalytic amount of a composition which is an iron
molybdenum material distributed interactively on a deboronated HAMS-1B
crystalline molecular sieve can yield aromatic aldehydes where the alkyl
substituent is methyl and alkenyl-substituted aromatics when the alkyl
substituent is larger than methyl. (oxidative dehydrogenation). The
compositions give a combination of both good yield and good catalyst
lifetime for the production of aromatic aldehydes or alkenyl aromatic
products with reduced amounts of burning to fully oxidized products. In
addition, the compositions show a selectivity in the oxidation of xylene
and dialdehydes which can serve as the basis for a process for separating
p-xylene from the other xylene isomers by selectively oxidizing p-xylene.
Products of such selective p-xylene and dialdehyde oxidation are suitable
intermediates for a variety of novel and specialty polymer applications
including liquid crystals, engineering polymers, and optical brighteners.
These oxidation products are also useful in synthesis of alcohols such as
cyclohexanedimethanol. A particularly useful product of this invention is
p-tolualdehyde which is useful as a feed to a water-based oxidation
process to make purified terephthalic acid.
SUMMARY OF THE INVENTION
In one aspect, the invention is a composition comprising a minor amount of
a material made from a first component which is a volatile compound of a
element selected from the group consisting of Fe(III), Zn(II), Zr(IV),
Nb(V), In(III), Sn(IV), Sb(V), Ce(III) and Bi(III) and a second component
which is a volatile compound of an element selected from the group
consisting of Mo(VI), W(VI) and V(V) which first and second components are
interactively distributed on a major amount of deboronated HAMS-1B
crystalline borosilicate molecular sieve containing less than about 0.1 wt
% of boron as the element. Advantageously, total metals in the minor
amount of material is in a range form about 0.5 to about 15 weight percent
of the total weight of the composition.
Preferred compositions include minor amount of a material consisting of a
first component which is a compound of an element selected from the group
consisting of Fe(III), Zn(IV), Sb(V), and Bi(III), and a second component
which is a compound of an element selected from the group consisting of
Mo(VI) and W(VI).
In a second aspect, the invention described herein is a composition
comprising a minor amount of iron molybdenum material with an atomic ratio
of molybdenum to iron in a range from about 1.5 to about 2.5 distributed
on a major amount of deboronated HAMS-1B crystalline borosilicate
molecular sieve containing less than about 0.05 wt % as the element of
boron.
In another aspect, the invention embraces a methyl-group oxidation process
comprising combining a feed containing a methyl aromatic compound with an
oxygen-affording substance at oxidation conditions over a composition
comprising a minor amount of an iron molybdenum material with an atomic
ratio of molybdenum to iron in a range from about 1.5 to about 2.5
distributed on a major amount of deboronated HAMS-1B crystalline
borosilicate molecular sieve containing less than about 0.1 wt % as the
element of boron.
In still another aspect, the invention embraces a composition made by a
process comprising:
depositing an iron compound on a HAMS-1B crystalline borosilicate molecular
sieve containing at least about 0.4 wt % as the element of boron or a
predeboronated HAMS-1B crystalline borosilicate molecular sieve containing
less than about 0.1 wt % as the element of boron from the vapor phase to
form an iron-containing deboronated HAMS-1B crystalline borosilicate
molecular sieve;
washing and drying said iron-containing deboronated HAMS-1B crystalline
borosilicate molecular sieve;
depositing a molybdenum compound on said washed and dried iron-containing
deboronated HAMS-1B crystalline borosilicate molecular sieve from the
vapor phase to form an iron-molybdenum-containing deboronated HAMS-1B
crystalline borosilicate molecular sieve; and
heating said iron-molybdenum-containing deboronated HAMS-1B crystalline
borosilicate molecular sieve to form a composition comprising a minor
amount of an iron molybdenum material having an atomic ratio of molybdenum
to iron in a range from about 1.5 to about 2.5 distributed on a major
amount of deboronated HAMS-1B crystalline borosilicate molecular sieve
containing less than about 0.1 wt % as the element of boron.
In still another aspect the invention is a separation process for a feed
comprising primarily xylenes including p-xylene comprising:
contacting said feed in an oxidation stage at oxidation conditions with an
oxygen-affording substance over a composition comprising a minor amount of
iron molybdenum material having a molybdenum to iron ratio between about
1.5 and about 2.5 distributed on a major amount of deboronated HAMS-1B
crystalline borosilicate molecular sieve containing less than about 0.1 wt
% as the element of boron to form an oxidized product;
separating said oxidized product into a primarily aromatic
aldehyde-containing product and a primarily xylene-containing product;
sending said primarily xylene-containing product to an isomerization stage;
and
recycling the isomerized product of said isomerization stage to said
oxidation stage.
In still another aspect the invention is an oxidative dehydrogenation
process comprising combining a feed containing at least one C.sub.2 to
C.sub.5 alkyl aromatic and/or C.sub.2 to C.sub.6 alkane hydrocarbon
compound with an oxygen-affording substance at oxidative dehydrogenation
conditions over a composition comprising a minor amount of an iron
molybdenum material having an atomic ratio of molybdenum to iron in a
range from about 1.5 to about 2.5 distributed on a major amount of
deboronated HAMS-1B crystalline borosilicate molecular sieve containing
less than about 0.1 wt % as the element of boron to form a C.sub.2 to
C.sub.5 alkenyl aromatic compound and/or C.sub.2 to C.sub.6 alkene
hydrocarbon compound. Typically, oxidative dehydrogenation is carried out
at temperatures above about 225.degree. C., preferably in a range from
about 250.degree. C. to about 550.degree. C.
In a still further aspect the invention is a process comprising combining a
benzene feed with nitric acid or nitrous oxide at oxidizing conditions
above about 350.degree. C. over a composition comprising a minor amount of
a material made from a first component which is a volatile compound of an
element selected from the group consisting of Fe(III), Zn(II), Zr(IV),
Nb(V), In(III), Sn(IV), Sb(V), Ce(III) and Bi(III), and a second component
selected from the group consisting of Mo(VI), W(VI) and V(V), which first
and second components are interactively distributed by vapor deposition on
a major amount of deboronated HAMS1-B crystalline borosilicate molecular
sieve containing less than about 0.1 wt % as the element of boron to form
primarily phenol.
In a still further aspect, the invention is a crystalline borosilicate
molecular sieve containing some lattice boron but less than about 0.05 wt
% and more than about 20 wt % silanol groups.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of this invention may be made directly from a AMS-1B
crystalline borosilicate molecular sieve in the hydrogen form, HAMS-1B, or
indirectly from a deboronated variation of such sieve. The preparation of
such a sieve is set out in detail in U.S. Pat. Nos. 4,268,420; 4,269,813;
and 4,285,919. A description of a particularly useful, essentially
sodium-free variant of HAMS-1B molecular sieve may be found in U.S. Patent
No. 5,053,211. All of such patents are specifically incorporated herein by
reference. Such HAMS-1B sieves contain characteristically between about
0.4 and about 1.1 wt % of lattice boron (about 2% of total boron) measured
as the element. However, they may have a larger total boron content as not
all the boron need be present as lattice boron.
In the direct procedure described below for making deboronated sieve, the
HAMS-1B sieve is first preferably aqueous ammonia exchanged and then
calcined between about 300.degree. C. and 700.degree. C. for a short
period of time before deposition of the metal compounds from the vapor
phase. Only a small loss of boron is noted in this preliminary aqueous
exchange and subsequent heating. If the deboronated sieve is made
indirectly (predeboronated HAMS-1B sieve) as is also described below, it
may also be calcined in the same temperature range before extracting the
boron and depositing the metal compounds from the vapor phase.
The deboronated HAMS-1B crystalline borosilicate molecular sieve of the
invention may be made directly, and preferably, by depositing the metal
compounds from the vapor state on HAMS-1B sieve, a process which is
involved in reducing the lattice boron content of the sieve during the
deposition process. The boron can then be water extracted from the sieve.
The sieve can also be made indirectly by extracting a HAMS-1B sieve with
deionized hot water or dilute acid prior to vapor deposition of the
metals. Preferably, the boron content of the sieve is reduced to less than
about 0.01 wt as the element, more preferably, less than about 0.05 wt %,
and most preferably, less than about 0.02 wt %, when the deboronated sieve
is made using either method. Made by either method, a small amount of
boron remains in the sieve along with some aluminum present as an
impurity.
The sieve retains the MFI structure of the original HAMS-1B sieve and may
be considered a high-silanol-containing silicalite. It is believed that
when the boron atoms are removed from the HAMS-1B sieve after the vapor
deposition process or the aqueous deboronation process, silanol-rich
reactive sites are left behind which are able to capture effectively the
metal compounds to form interactively catalytically active sites. The
silanol content of the deboronated HAMS-1B crystalline borosilicate
molecular sieve prior to vapor deposition, as determined by magic angle
spinning NMR, is preferably above about 15 wt %, more preferably, above
about 18 wt %, and most preferably, above about 20 wt % of the total
weight of the silicon atoms present in the sample. Weight percent silanol
in a sample is determined by the ratio of the area under the peak
corresponding to the HOSi(OSi).sub.3 NMR signal to the total areas of the
peaks corresponding to the Si(OSi).sub.4 and HOSi(OH).sub.3 signals.
Metal ions whose volatile compounds are particularly useful in making the
metal materials of this invention include Fe(III), Bi(III), Zr(IV), Sn(IV)
and Sb(V) as the first component. As the second component, the metals
whose compounds are particularly useful include Mo(VI), W(VI) and V(V).
After vapor depositing the two metal components on the sieve, the result
is heated to interact the compounds with each other and the sieve.
Depending upon the nature of the first and second component, it may be
desirable to switch the order of their depositing on the sieve. For
example, preferred Fe-Mo-DBH catalysts are obtained by distribution of an
iron compound followed by molybdenum compounds, however, preferred
Sb-Mo-DBH catalysts are obtained by distribution of an molybdenum compound
followed by antimony compounds.
The preferred combination of metal compounds forms an iron molybdenum
material which is made by vapor-depositing a volatile iron compound on the
sieve followed by vapor-depositing a volatile molybdenum compound on the
sieve and calcining the result to promote the interaction of the iron and
molybdenum compounds with each other and the sieve.
The process for making the catalytic compositions of the invention is
illustrated below using the preparation of a Fe-Mo-DBH composition. In
preparing the iron molybdenum material deboronated HAMS-1B composition,
the aqueous exchanged and calcined HAMS-1B sieve or calcined,
predeboronated HAMS-1B sieve is treated with a volatile iron compound such
as iron (III) chloride to deposit the iron compound on the sieve. The
amount of iron compound deposited on the surface of the sieve depends on
the amount of iron molybdenum material desired in the final composition.
Preferably, the iron-containing sieve is then washed to remove boron and
chlorine, and then it is calcined at a temperature between about
200.degree. C. and 400.degree. C. It has been found particularly
advantageous to the catalytic properties of the compositions to
vapor-deposit the iron compound on the sieve prior to vapor deposition of
the molybdenum compound.
The iron-containing sieve is then treated with a volatile molybdenum
compound such as MoO.sub.2 Cl.sub.2, MoOCl.sub.4, MoCl.sub.5, etc. to
vapor deposit the molybdenum compound on the sieve. Care should be taken
to lay down an amount of molybdenum to provide an atomic ratio molybdenum
to iron in a range upward from 1.5 which roughly corresponding to the
stoichiomety of the formula of iron molybdate, Fe.sub.2 (MoO4).sub.3.
Another calcination carried out at temperatures in a range from about
300.degree. C. to about 700.degree. C. is believed to promote interactions
of iron and molybdenum compounds, with each other and the sieve, to form
primarily iron molybdate. It is preferred not to have an excess of iron
over that corresponding to the iron molybdate formula given above, as the
presence of excess of iron appears to produce more hydrocarbon burning
during use of the composition as an catalyst. The major amount of the iron
molybdenum material seems to be in the form of finely divided iron
molybdate, Fe.sub.2 (MoO.sub.4).sub.3, and molybdenum trioxide, MoO.sub.3.
It is preferred to have an excess of molybdenum over that required for the
iron molybdate formula of 3 molybdenum atoms for each 2 Fe atoms.
Preferably, the molybdenum to iron atomic ratio of the deboronated HAMS-1B
compositions lies between about 1.5 to about 2.5, more preferably, between
about 1.6 and 2.4, and most preferably between about 1.6 and 2.3.
More generally, the atom ratio of the second component metal to the first
component metal of the metal material on the deboronated HAMS1-B
crystalline borosilicate molecular sieve is about 0.2 to 1 to about 3 to
1, more preferably, it is about 0.5 to 1 to about 2.5 to 1, and most
preferably, it is about 1 to 1 to about 2.5 to 1.
Generally, the total metals content of the interacted metal materials on
the deboronated sieves should be between about 0.5 and about 20 wt % of
the total composition. More specifically, the total metals in the iron
molybdenum material distributed on the deboronated HAMS-1B sieve is
desirably between about 0.5 and about 15 wt % based on the total
composition weight. More preferably, the total metals in the iron
molybdenum material distributed on the deboronated HAMS-1B sieve lies
between about 1 and about 12 wt %, and most preferably, the total metals
in the iron molybdenum material distributed on the sieve lies between
about 2 and about 10 wt %.
The oxidants useful in this invention for oxidation and oxidative
dehydrogenation are oxygen-affording substances such as air or mixtures of
oxygen with other gases such as nitrogen, argon, helium, carbon dioxide,
and the like. Use of carbon dioxide, as a carrier gas and/or
oxygen-affording substance alone or in combination with additional
oxygen-affording substances, appears to promote the conversion and
selectivity of the oxidation of p-xylene to aldehyde products and also
suppress substrate burning. Nitric acid and nitrous oxide are also useful
as oxidants for benzene in this invention.
The compositions of this invention are particularly useful as oxidation and
oxidative dehydrogenation catalysts, more particularly for the oxidation
of aromatic and methyl aromatic compounds and the oxidative
dehydrogenation of alkanes and alkyl aromatics, where the alkyl group is
larger than methyl. They can be used with nitric acid or nitrous oxide as
oxidants to oxidize benzene to phenol or nitrobenzene, depending upon the
reaction temperature. For example, methyl-substituted aromatics such as
methyl-naphthalenes, methylbiphenyls and methylbenzenes are conveniently
oxidized to aldehydes. Toluene, mixed xylenes and p-xylene are
particularly useful feeds. In the case of p-xylene, for example, both
p-tolualdehyde (TAL) and TPAA are formed. The compositions are also useful
in oxidizing ethylaromatics selected from the group consisting of
##STR1##
in which X is H, OCH.sub.3, NO.sub.2, OH, F, Cl, Br, COOH, COCl, R, COOR
and COR where R is a C.sub.1 to C.sub.4 alkyl group. The products of the
oxidation are aldehydes.
The compositions may also be used to oxidatively dehydrogenate alkanes, or
mixtures of alkanes, such as ethane, propane, butane, isobutane, pentane,
hexane and the like to the corresponding olefin or olefins, and C.sub.2
-C.sub.5 alkyl aromatics to aromatic alkenyl derivatives. The t-butyl
group of course is not included as it is not subject to partial oxidation
to an alkenyl group. For example, ethane is oxidatively dehydrogenated to
ethylene, ethylbenzene is oxidatively dehydrogenated to styrene,
p-diethylbenzene to divinylbenzene, and cumene is converted to
isopropenylbenzene.
It has been found the Fe-Mo-DBH compositions of this invention are poor at
catalyzing the oxidation of o-xylene and m-xylene to their respective
aldehydes and dialdehydes whereas the compositions are quite effective in
catalyzing the oxidation of p-xylene to its respective aldehyde and
dialdehyde. This difference believed to be a unique property of the
Fe-Mo-DBH compositions of this invention which may, in part, be the result
of the pore structure of the deboronated HAMS-1B sieve, allows the
oxidation process to be used to effect a separation of the isomers of
xylene or mixtures of xylene isomers with other hydrocarbons such as
ethylbenzene, and C.sub.9 paraffins and naphthenes by preferentially
forming para-tolualdehyde and TPAA from the p-xylene. Ethylbenzene can be
oxidatively dehydrogenated in the process to styrene. Reaction conditions
of oxidation over Fe-Mo-DBH compositions of this invention can readily be
selected to limit dehydrogenation reaction of ethylbenzene. The mixture of
aldehydes is easily separated from the unreacted xylenes by distillation,
for example, and can be further purified to remove the small amount of the
aldehydes and dialdehydes of o-xylene and m-xylene which are formed in the
oxidation process. The purified mixture of p-tolualdehyde and TPAA can
then be used to make pure TPAA or as intermediate for various applications
described herein above, for example, advantageously as a feed to a
water-based oxidation process for the preparation of terephthalic acid.
The unreacted xylenes from the oxidation stage after separation from the
aldehydes can be recycled to the alkyl group oxidation unit after first
being isomerized in a unit in which the amount of p-xylene is augmented.
In this manner, a feed of mixed xylenes can be continuously converted to
p-xylene oxidation products to form TPAA or to form an appropriate feed
for a water-based procedure for the preparation of terephthalic acid. The
details of a similar process using a cobalt boron and oxygen catalyst to
partially oxidize p-xylene and the use of the p-xylene oxidation products
in a water-based terephthalic acid process is taught in U.S. Pat. No.
4,863,888 which is specifically incorporated herein by reference.
The Fe-Mo-DBH compositions are also useful for the vapor or liquid phase
oxidation of benzene using nitric acid or nitrous oxide as the oxidant.
With these oxidants the product of the reaction is temperature sensitive.
Above about 350.degree. C. the oxidation produces primarily phenol, and
below about 400.degree. C. the oxidation produces primarily nitrobenzene.
The metal compound material distributed on deboronated HAMS-1B crystalline
borosilicate molecular sieve compositions useful in this invention can be
admixed with, or incorporated in, a silica or other oxide, such as
alumina, silica-alumina, thoria, titania, magnesia, a spinel, a
perovskite, bentonite and the like, as a binder. Preferably, a support
which is neutral to weakly basic or weakly acidic is desirable. Typically,
the compositions are incorporated within the binder by blending with a sol
of the oxide material and gelling the resulting mixture. These supported
compositions are then dried at temperatures in a range from about
100.degree. C. to about 200.degree. C. and thereafter generally calcined
at temperatures in a range from about 500.degree. C. to about 700.degree.
C.
If supported, the iron-molybdenum-material-loaded deboronated HAMS-1B sieve
(Fe-Mo-DBH) content of the supported compositions can vary anywhere from
about 5 to about 60 wt % of the total supported composition. Preferably,
they form about 10 to about 60 wt % of the total supported composition,
and more preferably, form about 10 to about 40 wt % of the total supported
composition.
Oxidation or oxidative dehydrogenation in the presence of the
above-described compositions is effected by contact of the organic
compound either in the liquid or vapor phase at temperatures ranging from
about 50.degree. C. to about 1000.degree. C. Generally, an
oxygen-containing gas is used as the oxidant. Air can be used or synthetic
mixture of an inert or other gas and the oxygen level adjusted to the
desired amount. The reaction takes place at atmospheric pressure, but the
pressure may be within the range of about 0 psig to about 2000 psig.
Reaction is suitably accomplished using a weight hourly space velocity of
between about 0.01 hr.sup.-1 and about 100 hr.sup.-1. For some compounds
reaction in the liquid phase is preferred. Reactions in the liquid phase
typically are carried out at temperatures in a range from about 50.degree.
C. to about 300.degree. C., preferably from about 100.degree. C. to about
260.degree. C. and most preferably from about 100.degree. C. to about
200.degree. C., with pressures in a range from about 0 to about 300 psig,
preferably from about 60 psig to about 250 psig at space velocities in a
range from about 0.02 hr.sup.-1 to about 5 hr.sup.-1, preferably from
about 0.08 hr.sup.-1 to about 2 hr.sup.-1. Liquid phase reactions can be
carried out in a trickle bed configuration, catalytic distillation
configuration or slurry bed configuration, for example. In the gas phase,
reactions typically are carried out at temperatures in a range from about
250.degree. C. to about 1000.degree. C., preferably from about 300.degree.
C. to about 600.degree. C. and most preferably from about 400.degree. C.
to about 550.degree. C., with pressures in a range from about 0 to about
300 psig, and space velocities in a range from about 0.01 hr.sup.-1 to
about 100 hr.sup.-1, preferably from about 0.5 hr.sup.-1 to about 50
hr.sup.-1. Gas-phase reactions can be carried out in a fluid bed, stirred
bed, fixed bed or other suitable reactor configuration.
Heat generated in the highly exothermic liquid-phase partial oxidation is
typically dissipated at least partially by vaporization of unreacted
aromatic reactant and, if used, solvent, in the partial oxidation reactor.
The resulting vapor and excess oxygen-containing gas are withdrawn from
the partial oxidation reactor through a vent above the liquid level in the
partial oxidation reactor. The withdrawn aromatic reactant is then
condensed in a condenser and recycled to the partial oxidation reactor
The oxidation or oxidative dehydrogenation of the method of this invention
can be performed in either a batch or semi-continuous mode. In the batch
mode, the aforesaid aromatic reactant, catalyst and, if used, solvent are
initially introduced batchwise into the reactor, and the temperature and
pressure of the reactor contents are then raised to the desired levels
therefor for the commencement of the oxidation reaction. An
oxygen-containing gas or vapor is introduced continuously into the
reactor. After commencement of the oxidation reaction, the temperature of
the reactor contents is raised to the desired reaction temperature. In the
semi-continuous mode, the catalyst and, if used, solvent are initially
introduced batchwise into the reactor, and then the aromatic reactant and
air are introduced continuously into the reactor. After commencement of
the oxidation reaction, the temperature of the reactor contents is raised
to the desired reaction temperature. Preferably, the continuous mode is
employed for the vapor or liquid phase oxidation or oxidative
dehydrogenation method of this invention.
If the partial oxidation of the method of this invention is performed
semicontinuously, the space velocity in the range of from about 0.02
hr.sup.-1, preferably from about 0.08 hr.sup.-1, to about 5 hr.sup.-1,
preferably to about 2 parts of the aromatic reactant per part of the
catalyst particles by weight per hour is employed. If the partial
oxidation of the method of this invention is performed batchwise, the
aromatic reactant and catalyst are mixed in a weight ratio in the range of
from about 250, preferably from about 1000, to about 10,000, preferably to
about 4000 parts of aromatic feed per part of catalyst by weight, and the
reaction time is in the range of from about 0.5, preferably from about 1,
to about 20, preferably to about 4 hours.
The resulting partially oxidized liquid aromatic product can then be
separated from the solid catalyst particles by any convenient solid-liquid
separation. The aromatic product can also be separated from any unreacted
aromatic reactant by any convenient liquid-liquid separation, such as
distillation, by any convenient gas-liquid separation if the unreacted
aromatic reactant has been vaporized or by any convenient solid-liquid
separation if the temperature is lowered to a point where the partially
oxidized aromatic product but not the aromatic reactant crystallizes.
An especially convenient means of both effecting the partial oxidation and
separating the partially oxidized, aromatic product from both the catalyst
and unreacted aromatic reactant involves catalytic distillation. In such a
system, a distillation column in the partial oxidation reactor is packed
with a bed of the solid heterogeneous catalyst and is heated to a
temperature in the range of suitable reaction temperatures for the partial
oxidation. In addition, at least the bottom region of the catalyst bed is
maintained at the temperature of at least the boiling point of the
aromatic reactant and at least the melting point of the partially oxidized
aromatic product but below the boiling point of the partially oxidized,
aromatic product, at the pressure employed in the column. Liquid aromatic
reactant is introduced into the top of the column and passes downwardly
through the column. An oxygen-containing gas is introduced into the bottom
of the column and flows upward through the column. The liquid aromatic
reactant and oxygen react to form the partially oxidized aromatic product
which flows as a liquid downward through the column. Any remaining
unreacted aromatic feed continues to flow downward through the column
until it vaporizes in the bottom region thereof and then flows upward
through the column in the stream of oxygen-containing gas.
Thus, substantially only partially oxidized, aromatic product passes
downward out of the column as a liquid and thereby is separated from both
the solid catalyst and unreacted aromatic reactant even before it is
withdrawn from the partial oxidation reactor. The resulting aromatic
product withdrawn from the partial oxidation reactor is substantially free
of unreacted aromatic reactant and contains preferably less than 10 weight
percent, more preferably less than 1 weight percent of unreacted aromatic
reactant.
In the alternative, a trickle bed catalyst configuration can be employed,
in which case both unreacted aromatic reactant and partially oxidized
aromatic product pass as a mixture of liquids out of the catalyst bed. In
such case, it would be necessary to separate the unreacted aromatic
reactant from the partially oxidized aromatic product.
In a preferred embodiment of this invention, the partially oxidized
aromatic product produced from p-xylene or mixed xylenes as described
herein above is completely oxidized to its carboxylic acid derivative in
at least one additional step. Preferably such complete oxidation to the
carboxylic acid derivative occurs in a second reactor using a suitable
oxidation catalyst dissolved or suspended in water solution.
The partially oxidized p-xylene, etc., product of the partial oxidation
method of the present invention is soluble in water as well as in other
common solvents such as low molecular weight carboxylic acids such as
acetic acid. Hence, it a preferred embodiment of the method of this
invention, the partially oxidized aromatic product is introduced into a
second reactor where it is completely oxidized in the liquid phase by an
oxygen-containing gas to its corresponding carboxylic acid derivative.
Either the partially oxidized product is introduced directly into the
second reactor where it dissolves in water or a mixed solvent already in
the second reactor, or the partially oxidized aromatic product is first
dissolved in water or a mixed solvent and the resulting solution is
introduced into the second reactor. In either case, the weight ratio of
partially oxidized aromatic product introduced into the second
reactor-to-water (or other solvent) is in the range of from about 0.1
preferably from about 0.2, to about 0.4, preferably to about 0.3 parts of
the partially oxidized aromatic product per part by weight of water.
The following Examples will serve to illustrate certain specific
embodiments of the herein disclosed invention. These Examples should not,
however, be construed as limiting the scope of the novel invention as
there are many variations which may be made thereon without departing from
the spirit of the disclosed invention, as those of skill in the art will
recognize.
GENERAL
All the metal-containing deboronated HAMS-1B sieve compositions were
pressed into 11/8 in diameter tablets at 10,000 psig, crushed and sieved
to 20/40 mesh size (ASTME-11) for use in testing of catalytic activity.
EXAMPLE 1
Using the indirect method for making DBH, a 427 g amount of HAMS-1B sieve
containing 1.5 wt % of boron was stirred with 3.5 L of deionized water for
4 hr. The solid was recovered and washed three times for 4 hr each with
deionized water at 90.degree. C. It was then oven-dried at 110.degree. C.
overnight yielding 376 g of dried product which contained 0.26 wt % of
boron by ICP analysis. The silanol content by .sup.29 Si MAS NMR analysis
was 19 wt %. A 10 g sample of the solid was water-extracted using a
Soxhlet extractor for 4 days. After oven drying at 110.degree. C.
overnight, an 8.6 g amount of solid remained which contained 0.013 wt % of
boron by ICP analysis and 21 wt % of silanol groups by .sup.29 Si MAS NMR.
The resulting solid was a pre-DBH ready to undergo metal compound
deposition to make a metal-compound-containing composition.
EXAMPLE 2
Using the direct method for making DBH, a 350 g sample of HAMS-1B sieve
containing about 1.8 wt % of boron was exchanged using an ammonium acetate
solution (150 g of ammonium acetate in 3.5 L of water) with stirring at
ambient temperature for 30 min. The result was filtered and dried and the
exchange procedure repeated twice more. Dried exchanged HAMS-1B sieve was
calcined for 4 hr at 540.degree. C. and when analyzed contained 1.18 wt %
boron by ICP analysis. Calcination was repeated once more at 600.degree.
C. to reduce iron compound pickup in the next step.
Dried and exchanged sieve was again calcined at 400.degree. C. and put in a
tube and dry nitrogen containing anhydrous FeCl.sub.3 passed over the
sieve at 460.degree. C. The sieve was removed from the tube, cooled,
heated at 90.degree. C. in deionized water for 1.5 hr, and then filtered
and dried. This procedure was repeated twice more. The resulting
iron-loaded sieve contained 2.2 wt % of iron and 0.06 wt % of boron by ICP
analysis.
Iron-loaded sieve was treated in a process similar to that for iron loading
at about 200.degree. C. with MoO.sub.2 Cl.sub.2 yielding a iron-molybdenum
material loaded sieve containing 1.94 wt % Fe and 7.2 wt % Mo. The solid
was heated at 650.degree. C. for 8 hr in air to fix molybdenum.
Calcined solid was washed using the wash procedure outlined above, and when
analyzed after washing, contained 0.099 wt % B, 2.09 wt % Fe, and 4.9 wt %
Mo wt % by ICP analysis (Mo/Fe=1.35). Raman spectra of these catalysts had
bands at 1324 cm which were due to .varies.-FeO.sub.3. Not all of the iron
compound reacted with the molybdenum compound to form Fe.sub.2
(MoO.sub.4).sub.3.
Catalyst (2 g) was pretreated in a flow of 100 mL/min of 8 vol % O.sub.2 in
N.sub.2 at 650.degree. C. for 16 hr and then cooled to 375.degree. C. In
testing this catalyst for oxidation, p-xylene containing feed having an
O.sub.2 /PX molar ratio of 7 was converted at a temperature of 375.degree.
C., a WHSV of 0.37 hr.sup.-1, and contact time of 0.16 sec using a gas
flow of 250 mL/min of 8 vol % O.sub.2 in N.sub.2 mixed with 1250 mL/min of
N.sub.2. Oxidation results were 58% PX conversion, 27% CO.sub.2
selectivity, 18% TAL selectivity, and 49% TPAA selectivity.
Powder X-ray diffraction pattern (XRD) of iron-molybdenum material loaded
sieve (Fe-Mo-DBH) showed that the crystal structure of HAMS-1B sieve was
maintained, but the pattern had considerably reduced peak intensities. BET
surface area remained about that of the starting sieve, 288 m.sup.2 /g.
Micropore volume was 0.114 cc/g. Raman spectra showed peaks at about 784
cm.sup.-1 and 956 cm.sup.1 which were atributed to Fe.sub.2
(MoO.sub.4).sub.3., and other peaks at about 670 cm.sup.-1, 822 cm.sup.-1,
and 998 cm.sup.-1 which were atributed to MoO.sub.3.
EXAMPLE 3
Fe-Mo-DBH was made according to the chemical vapor deposition (CVD)
procedure of Example 2, but using MoCl.sub.5 for Mo deposition. It was
analyzed and contained 1.5 wt % Fe and 5.2 wt % Mo (Mo/Fe=2.05). Catalyst,
1 mL (0.521 g) was loaded into a micro-quartz reactor equipped with an
on-line GC, and calcined in the reactor at 675.degree. C. for 16 hours.
Calcined catalyst was tested in oxidation of a p-xylene stream (1 vol %
O.sub.2, 1 vol % N.sub.2, 0.1 vol % p-xylene, and balance He) under the
following conditions:
Temperature: 350.degree. C.,
Flow rate: 400 sccm,
Contact time: 0.15 sec,
WHSV: 0.22 hr.sup.-1,
Molar ratio of O.sub.2 /PX: 10/1.
Effluent gas was analyzed with the on-line GC, and the results were 67%
p-xylene conversion, 9% COx (CO.sub.2 +CO)) selectivity, 28% TAL
selectivity, 50% TPAL selectivity, 9% toluic acid selectivity, and 4%
benzoic acid plus toluene selectivity.
EXAMPLE 4
The gas phase oxidation of Example 3 was repeated except the feed gas
contained 4.0 vol % O.sub.2, 4.0 vol % N.sub.2, and 0.1 vol % p-xylene in
He (molar ratio of O.sub. /PX=40). Results were 78% PX conversion, 20% COx
selectivity, 17% TAL selectivity, 46% TPAA selectivity, 13% maleic
anhydride selectivity, and 5% benzoic acid plus toluene selectivity. While
obtaining PX conversion of 78% at an unusually high molar ratio of O.sub.2
/PX, this example demonstrated, advantageously, only moderate burning.
EXAMPLE 5
Another Fe-Mo-DBH was made according to the chemical vapor deposition (CVD)
procedure of Example 2, but using MoOCl.sub.2 for Mo deposition. It was
analyzed and contained 2.55 wt % Fe, 14.5 wt % Mo, and 0.05 wt % B
(Mo/Fe=3.3). Catalyst (2 g) was loaded into a micro-quartz reactor
equipped with on-line GC, and treated with air at 400.degree. C. for 1 hr.
Treated catalyst was tested in oxidation of a p-xylene stream at
375.degree. C. by pumping PX at a rate of 0.77 g/hr into a flowing gas
mixture of 500 mL/min of 6 vol % O.sub.2 in N.sub.2, and 1000 mL/min pure
N2. The effluent stream was analyzed by GC, and results were 20% PX
conversion, 37% COx selectivity, 28% TAL selectivity and 39% TPAL
selectivity.
After this run at 375.degree. C. the Fe-Mo-DBH catalyst was calcined in the
reactor at 680.degree. C. for 1 day and another p-xylene oxidation was
carried out under identical conditions. A remarkable improvement in
catalyst performance was observed. Conversion of p-xylene was increased
from 20% to 68% and selectivity to TPAL and TAL were also improved,
respectively, from 39% to 47% and from 18% to 21%, while CO.sub.2
selectivity decreased from 37% to 19%.
Subsequently, the Fe-Mo-DBH catalyst was further calcined in situ with air
at 695.degree. C. for a prolonged period (1 day and then an additional 4
days). During the calcining period, iron remained intact on the catalyst
while excess MoO.sub.3 was continually sublimed off to a final level of
7.0 wt % Mo. Thus the molar ratio Mo/Fe became 1.8 at the end of this
calcination. Treated catalyst was tested in oxidation of a p-xylene stream
at varying reaction temperatures. Following is a summary of results
obtained.
TABLE 1
______________________________________
PX Oxidation Over a Fe--Mo--DBH
Temp., PX conv. Selectivity, % Yield, %
.degree.C.
% TPAL TAL COx TPPAL TAL
______________________________________
375 32 54 28 14 17 9
(1 day calcination at 695.degree. C.)
(After 4 more days calcination at 695.degree. C.)
375 17 58 27 13 9 5
425 43 60 18 18 26 8
500 74 64 9 21 47 7
564 83 60 6 28 50 7
510 79 67 9 19 53 7
500 74 64 9 21 47 7
______________________________________
Mole ratio O.sub.2 /PX was 40
EXAMPLE 6
A Fe-Mo-DBH catalyst treated as in the initial step of Example 5 with air
at 400.degree. C. for 1 hr (Mo/Fe=3.3), and then was calcined in the
reactor at 675.degree. C. for 16 hours. The Fe-Mo-DBH catalyst obtained
had a molar ratio Mo/Fe of 1.8. Calcined catalyst was tested in oxidation
of a p-xylene stream at the conditions used in Example 3. Results were 76%
p-xylene conversion, and selectivities to TPAL, TAL and COx were,
respectively, 54%, 26% and 17%.
EXAMPLE 7
Another Fe-Mo-DBH catalyst was made according to the chemical vapor
deposition (CVD) procedure of Example 2, but using MoOCl.sub.4 for Mo
deposition. It was analyzed and contained 1.2 wt % Fe, 4.8 wt % Mo, and
272 ppm B (Mo/Fe=4.2). Raman spectrum of this catalyst show peaks for
Fe.sub.2 (MoO.sub.4).sub.3 and MoO.sub.3 phases, but the .alpha.-Fe.sub.2
O.sub.3 phase, an active species for promoting burning, was absent.
Catalyst (1 mL, 0.52 g) was tested in a micro-reactor for oxidation of
p-xylene under identical conditions used in Example 3 at varying
temperatures of reaction. Following is a summary of results obtained.
TABLE 2
__________________________________________________________________________
PX Oxidation Over a Fe--Mo--DBH
Temp PX Selectivity, % Yield, %
.degree.C.
% TPAL
TAL
BA TOL
MA CO CO2
TPAL
TAL
__________________________________________________________________________
250 6.6
20.4
45.4
-- 9.6
-- 16.3
7.5
300 15.5
38.0
44.7
1.3
1.6
-- 6.1
8.4
5.9 6.9
325 23.8
47.3
33.3
1.5
1.3
2.2
4.2
9.1
9.8 7.9
350 42.8
48.6
29.2
1.9
1.4
4.0
4.3
10.6
20.8
12.5
375 69.2
42.2
25.2
2.2
1.7
6.8
5.8
16.1
29.2
17.4
400 89.1
35.7
19.3
2.1
1.7
9.2
8.2
23.3
31.8
17.2
__________________________________________________________________________
TOL: toluene,
BA: benzaldehyde,
MA: maleic anhydride
EXAMPLE 8
A 350 g sample of HAMS-1B sieve containing about 1.8 wt % of boron was
exchanged using an ammonium acetate solution (150 g of ammonium acetate in
3.5 L of water with stirring at ambient temperature for 30 min. The result
was filtered and dried. Dried exchanged HAMS-1B sieve was calcined for 5
hr at 660.degree. C. and when analyzed using the ICP technique contained
0.9 wt % boron.
Dried and exchanged sieve was again calcined at 400.degree. C., loaded into
a tube and dry nitrogen containing anhydrous FeCl.sub.3 passed over the
sieve at 460.degree. C. The sieve was removed from the tube, cooled,
heated at 90.degree. C. in deionized water for 1.5 hr and then filtered
and dried. This procedure was repeated twice more. The resulting product
was 1.5 wt % iron and 0.134 wt % boron by ICP analysis.
Iron loaded sieve was treated, by a process similar to the iron loading
procedure, with MoO.sub.2 Cl.sub.2 yielding iron-molybdenum loaded sieve
containing 1.5 wt % iron and 8.4 wt % molybdenum. The material was heated
650.degree. C. for 8 hr in nitrogen and washed three times and when
analyzed by ICP was 1.62 wt % iron and 3.05 wt % molybdenum.
Iron-molybdenum loaded sieve was treated, in a process similar to the
molybdenum loading procedure, with WOCl.sub.4 yielding an iron-tungsten
material loaded sieve containing 1.2 wt % Fe, 10.2 wt % W and 0.11 wt %
Mo. After tungsten deposition, the material was removed from the tube and
calcined in air at 650.degree. C. for 8 hr. Tungsten deposition was
carried out at 290.degree. C. instead of 220.degree. C. This higher
temperature allowed more molybdenum to vaporize from the sieve.
A 1 mL sample (0.52 g) was loaded into a micro reactor and fed a stream
composed of 1 vol % O.sub.2, 1 vol % N.sub.2, 0.1 vol % PX in He at a WHSV
of 0.114 hr.sup.-1. The oxidation results obtained are shown below in
Table 3.
TABLE 3
______________________________________
PX Oxidation Over a Fe--W--DBH
Temperature, .degree.C.
350 375 400
______________________________________
PX Conversion, %
46 67 87
O.sub.2 Conversion, %
18 31 58
Selectivities.sup.1
Benzene 0.3 0.6 1.1
toluene 10.5 8.6 6.8
Maleic Anhydride
8.4 11.5 16.8
Benzaldehyde 1.2 1.8 2.3
TAL 12.7 9.7 5.9
TPAA 23.8 26.1 21.5
CO 2.0 3.6 6.4
CO.sub.2 11.2 18.2 29.7
______________________________________
.sup.1 Mol % of the product based upon the total xylene convert
COMPARATIVE EXAMPLE 9
A mixed oxide of iron and molybdenum on silica was prepared using a
co-formation technique by adding aqueous solutions of ammonium
paramolybdate and Fe(III) nitrate to Nalco silica gel 1034A with vigorous
agitation over a period of several hours. After standing, the gel was
dried in a vacuum oven, calcined, and sieved to a 20/40 mesh particle
size. The mixed oxide material was 2.58 wt % Mo and 0.93 wt % Fe by ICP
analysis (Mo/Fe=1.6). Results using this mixed oxide material to catalyze
oxidation of p-xylene are shown in Table 4 below.
TABLE 4
______________________________________
PX Oxidation Over Co-formed Fe and Mo on Silica.sup.1,2
Temp. PX Conv. Selectivities, %
.degree.C.
% TPAA TAL CO.sub.2
______________________________________
375 4.5 10 18 67
______________________________________
.sup.1 O.sub.2 /PX of feed was 10 in N.sub.2
.sup.2 WHSV = 0.385 hr.sup.-1 (2g catalyst)
EXAMPLE 10
Two Fe-Mo-DBH compositions were made starting with an ammonium acetate
exchanged HAMS-1B sieve containing 0.87 wt B and 33.5 wt % Si. Results for
p-xylene oxidation at 375.degree. C. over the two materials is shown below
in Table 5.
TABLE 5
______________________________________
Effect of Different Mo/Fe Ratios on the PX
Oxidative Properties of Fe--Mo--DBH
% % Mo/Fe Total PX Selectivities, %
B Mo Ratio Metals g
Conv. %
TPAA TAL CO.sub.x
______________________________________
0.05 9.9 3.3 11.61 20.3 39 18 37
* 6.9 1.8 8.8 54 51 23 18
______________________________________
* not measured
EXAMPLE 11
Soxhlet extraction of HAMS-1B sieve with water for a period of two days
obtained a DBH sieve having 121 ppm of boron. The deboronated sieve was
treated in the vapor phase at about 450.degree. C. with FeCl.sub.3
yielding a solid which was washed and dried. A portion (4.7 g) of Fe-DBH
was treated with MoO.sub.2 Cl.sub.2 in the vapor phase at about
200.degree. C. yielding a yellow-green solid which was calcined and washed
with deionized water several times. Analysis by ICP was 7.5 wt % Mo and
2.37 wt % Fe (Mo/Fe=1.84). The product, Fe-Mo-DBH, had BET surface area of
about 286 m.sup.2 /g. Table 6 below shows results of catalytic oxidation
of p-xylene.
TABLE 6
______________________________________
Oxidation of PX Over Calcined and Uncalcined
Pre-deboronated Fe--Mo--DBH.sup.1,2,3
Temp. PX Conv. Selectivities, %
.degree.C.
% TPAA TAL TOL CO.sub.x
______________________________________
275 6 12.7 48.4 17.5 7.5
(7) (14.0) (52.1) (16.2) (12.2)
300 13 34 44.5 6.8 8.4
(13) (20.3) (52.0) (9.9) (13.6)
325 24 28.7 48.4 6.1 11.5
(26) (22.5) (44.7) (7.6) (22.1)
350 43 29.8 39.7 5.7 18.5
(49) (20.6) (32.9) (6.7) (34.3)
375 68 24.3 29.0 5.1 33
(84) (10.7) (17.4) (5.4) (58.3)
______________________________________
.sup.1 Feed is 1.0% O.sub.2, 1.0% N.sub.2 and 1.0% PX in He.
.sup.2 Calcination at 700.degree. C. for 13 hr
.sup.3 Values in parenthesis are for uncalcined Fe--Mo--DBH
EXAMPLE 12
A 420 g amount of HAMS-1B sieve was heated at reflux with 3.5 L of
deionized water for about 3 hr, solids separated and dried at ambient
temperature. This procedure was repeated. Resulting solids were calcined
at temperatures up to a temperature of 550.degree. C. A portion of
calcined solid was treated with BiCl.sub.3 at about 460.degree. C. The
BiCl.sub.3 deposited solid was washed and dried. ICP analysis gave less
than 0.01 wt % Cl.sup.-, 5.1 wt % Bi and 0.45% B. After another
calcination at 500.degree. C. for 2 hr, the Bi-DBH was heated with
MoO.sub.2 Cl.sub.2 at about 200.degree. C. Resulting catalyst was washed
and dried. ICP analysis showed catalust contained 5.1 wt % Bi and 3.84 wt
% Mo (Mo/Bi=2.0). The Bi-Mo-DBH was used to oxidize p-xylene with the
results shown in Table 7 below.
TABLE 7
______________________________________
PX Oxidation Over a Bi--Mo--DBH
Temp. PX Conv. Selectivities, %
.degree.C.
% TPAA TAL CO.sub.x
______________________________________
375 10.8 32 44 22
425 29.0 27 67 23
______________________________________
EXAMPLE 13
A 420 g amount of HAMS-1B sieve was heated at reflux with 3.5 L of
deionized water for about 3 hr and then solids were separated and dried at
ambient temperature. The procedure was repeated. Resulting solids were
calcined at temperatures up to a maximum temperature of 550.degree. C. A
portion, 62.6 g, of calcined solid was treated with MoO.sub.2 Cl.sub.2 at
about 200.degree. C. and then steamed for 2 hr resulting in 69.9 g of
yellow-green solid. ICP analysis gave less than 0.01 wt % Cl.sup.- and
4.09 wt % Mo. Antimony was put on 1 g of Mo-DBH by vapor deposition at
150.degree.-250.degree. C. using SbCl.sub.3 and the resulting solid
steamed. A 7.6 g amount of yellow-green solid was produced which was
washed 3 times with deionized water and oven dried. Chloride content of
the Sb-Mo-DBH was less than 0.1 wt %. The Sb and Mo contents were,
respectively, 4.5 and 6.5 wt % (Mo/Sb=1.80). Catalytic results are shown
below in Table 8.
TABLE 8
______________________________________
PX Oxidation over Sb--Mo--DHB.sup.1
Temp. PX Conv. Selectivities, %
.degree.C.
% TPAA TAL Toluene
CO.sub.x
______________________________________
475 30 41.8 18.3 12.2 23.6
500 68 36.6 11.2 16.1 28.5
______________________________________
.sup.1 Feed is 0.1 vol. % PX, 1.0 vol. % O.sub.2, 1.0 vol. % N.sub.2 in
helium
EXAMPLE 14
A Zn-Mo-DBH catalyst which analyzed 9.5 wt % Mo and 2.4 wt Zn, was prepared
according to the CVD procedure of Example 2 except that an aqueous
solution of zinc nitrate was used to make an impregnated Zn-DBH (dried at
400.degree. C.) prior to applying a CVD step with MoO.sub.2 Cl.sub.2.
After catalyst was loaded into a micro-reactor and calcined 16 hrs at
680.degree. C., p-xylene was oxidized at 450.degree. C. under identical
conditions described in Example 3. Results were 59% PX conversion, 40%
TPAL selectivity, 27% TAL selectivity, 31% COx selectivity, and 2% toluene
selectivity
EXAMPLE 15
Fe-Mo-DBH was made according to the CVD procedure of Example 2, but using
MoCl.sub.5 for Mo deposition. It was analyzed and contained 2.15 wt % Fe,
5.8 wt % Mo, and 269 ppm B (Mo/Fe=1.57). Fe-Mo-DBH catalyst (0.335 g) was
tested in oxidation of a mixed xylene feed (PX/MX/OX was 1/2/1) stream of
2 vol % O.sub.2, 2 vol % N.sub.2, and balance He. Results are shown in
Table 9 below.
TABLE 9
______________________________________
Oxidation of a Mixed Xylene Stream Over Fe--Mo--DBH
Xyl. PX Selectivities
Temp. Conv. Conv. p-TAL m- / o-TAL
TPAA CO.sub.x
.degree.C.
% % % % % %
______________________________________
300 1 3 92 * * 8
325 2 7 52 * 47 1
350 4 15 43 * 44 14
375 8 29 39 * 46 15
400 13 45 35 * 48 17
425 21 64 28 4 48 18
450 28 80 22 7 48 21
475 35 92 18 14 41 25
______________________________________
* negligible
EXAMPLE 16
The same catalyst composition used in Example 15 was used in this Example
to oxidize a stream containing 0.14 vol % of o-xylene, 6 vol % O.sub.2,
and 6 vol % N.sub.2 in helium. The O.sub.2 to o-xylene ratio was 43.
Results are shown in Table 10 below.
TABLE 10
______________________________________
Oxidation of o-Xylene Over Fe--Mo--DBH
Temp., .degree.C.
350 400 450 500
______________________________________
o-Xyl Conv., %
6 14 23 53
Selectivities, %
TEBPM.sup.1 * 21 14 12
PLCA.sup.4 17.9 7.6 1.6 0.2
o-TAL.sup.2 33 14 24 27
THAL.sup.3 Trace Trace Trace Trace
THAN.sup.4 29 21 20
CO.sub.x 66 36 41 41
______________________________________
.sup.1 TEBPM is trimethylbiphenylmethane
.sup.2 oTAL is otolualdehyde
.sup.3 THAL is phtalaldehyde
.sup.4 THAN is phthalic anhydride
* negligible
EXAMPLE 17
Fe-Mo-DBH was made according to the CVD procedure of Example 2. It was
analyzed and contained 1.77 wt % Fe and 6.9 wt % Mo (Mo/Fe=2.3). Fe-Mo-DBH
catalyst (0.511 g) was tested in oxidation of o-xylene in a stream of 2
vol % O.sub.2, 2 vol % N.sub.2, and balance He under the following
conditions at varying temperatures.
______________________________________
WHSV: 0.28 hr.sup.-1,
Contact time: 0.105-0.21 sec.
______________________________________
Results are shown in Table 11 below.
TABLE 11
______________________________________
Oxidation of o-Xylene Over Fe--Mo--DBH
Temp., .degree.C.
250 400 500 550
______________________________________
o-Xyl Conv., %
0 8.6 77.1 97.0
Selectivities, %
TEBPM.sup.1 * 7.6 13.9 18.6
Benzaldehyde * 0.9 0.6 0.7
o-TAL.sup.2 * 47.8 58.5 41.5
THAL.sup.3 * 0.8 2.1 2.1
THAN.sup.4 * 7.8 8.1 18.3
MAN.sup.5 * 8.9 7.4 8.3
CO 0 6.6 3.7 5.9
CO.sub.2 0 19.0 5.9 5.7
______________________________________
.sup.1 TEBPM is trimethylbiphenylmethane
.sup.2 oTAL is otolualdehyde
.sup.3 THAL is phtalaldehyde
.sup.4 THAN is phthalic anhydride
.sup.5 MAN is maleic anhydride
* negligible
EXAMPLE 18
Fe-Mo-DBH was made according to the CVD procedure of Example 2. Fe-Mo-DBH
catalyst was analyzed and contained 1.61 wt % Fe and 7.2 wt % Mo
(Mo/Fe=2.6). This catalyst (10 g) was impregnated with an aqueous
AgNO.sub.3 solution (0.133 g AgNO.sub.3 was dissolved in 15 mL deionized
water) by the incipient wetness method. Silver impregnated catalyst,
Ag/Fe-Mo-DBH, was analyzed and contained 6.2 wt % Mo, 1.85 wt % Fe, and
760 ppm Ag. It was pressed and sieved to 20/40 mesh size. Ag/Fe-Mo-DBH
catalyst (1.4 mL, (0.51 g) was loaded into a micro-reactor, and oxidation
of o-xylene was carried out in a gas stream comprised of 2 vol % O.sub.2
and 2 vol % N.sub.2 in He. Results summarized in Table 12, demonstrated
that side reactions occurring in the oxidation with Fe-Mo-DBH, such as
disproportionation of o-xylene to toluene and pseudocumene, and
dehydrocoupling of o-xylene to trimethylbiphenylmethane, can be suppressed
by incorporating Ag into Fe-Mo-DBH catalyst.
Oxidation of o-xylene was at at varying temperatures under the following
conditions.
______________________________________
WHSV: 0.28 hr.sup.-1,
Contact time: 0.09 sec,
Temperature: 400-550.degree. C.
______________________________________
Results are shown in Table 12 below.
TABLE 12
______________________________________
Oxidation of o-Xylene Over Ag/Fe--Mo--DBH
Temp., .degree.C.
400 450 500 550
______________________________________
o-Xyl Conv., %
8.1 22.8 53.0 71.3
Selectivities, %
TEBPM.sup.1 3.2 4.6 8.3 8.8
Benzaldehyde * 0.3 0.4 0.9
o-TAL.sup.2 78.6 83.5 75.7 64.2
THAL.sup.3 0.3 0.6 0.9 0.9
THAN.sup.4 2.8 3.0 5.6 9.1
MAN.sup.5 * * 1.6 2.6
CO 0 0 1.8 3.5
CO.sub.2 15 7.9 5.2 9.5
______________________________________
.sup.1 TEBPM is trimethylbiphenylmethane
.sup.2 oTAL is otolualdehyde
.sup.3 THAL is phtalaldehyde
.sup.4 THAN is phthalic anhydride
.sup.5 MAN is maleic anhydride
* negligible
COMPARATIVE EXAMPLE 19
A 1.4 g (0.8 mL) sample of ferric molybdate, Fe.sub.2 (MoO.sub.4).sub.3,
20-40 mesh size, was loaded into a micro-reactor, and o-xylene oxidized in
a gas stream comprised of 2 vol % O.sub.2 and 2 vol % N.sub.2 in He. In a
typical run at 400.degree. C., only 0.4 vol % of o-xylene was. converted
to give o-tolualdehyde (83% selectivity), phthalaldehyde(8.8%
selectivity), and phthalic anhydride(8.0% selectivity) without burning.
Oxidation of o-xylene was carried out at varying temperatures under the
following conditions .
______________________________________
WHSV: 0.10 hr.sup.-1,
Contact time: 0.07 sec,
Temperature: 400-600.degree. C.
______________________________________
Results are shown in Table 13 below.
TABLE 13
______________________________________
Oxidation of o-Xylene Over Fe.sub.2 (MoO.sub.4).sub.3
Selectivities, %
Temp., .degree.C.
o-Xyl Conv. o-TAL.sup.2
THAL.sup.3
THAN.sup.4
______________________________________
400 0.4 83.2 8.8 8.0
500 1.0 88.7 4.6 3.6
600 13.8 87.9 5.7 4.0
______________________________________
.sup.2 oTAL is otolualdehyde
.sup.3 THAL is phtaladehyde
.sup.4 THAN is phthalic anhydride
EXAMPLE 20
The same catalyst composition used in Example 15 was used in this Example
to oxidize a stream containing 0.14 vol % of m-xylene, 6 vol % O.sub.2,
and 6 vol % N.sub.2 in helium. The O.sub.2 to m-xylene ratio was 43.
Results are shown in Table 14 below.
TABLE 14
______________________________________
Oxidation of m-Xylene Over Fe--Mo--DBH
Temp. m-Xyl Conv. Selectivities %
.degree.C.
% m-TAL CO.sub.x
______________________________________
350 3 67 33
400 9 33 67
450 20 65 34
500 44 58 39
______________________________________
EXAMPLE 21
In this example separation of p-xylene from its isomer mixture was obtained
by preferential oxidation of p-xylene over Fe-Mcatalyscatalyst. Fe-Mo-DBH
catalyst having an pre-oxidation analysis by ICP of 2.15 wt % Fe, 5.8 wt %
Mo, and 269 ppm B (Mo/Fe=1.57), was intermittently used in gas phase
oxidation screening reactions with xylene isomers for about six months.
Used catalyst was removed from the reactor and analyzed by ICP to contain
2.15 wt % Fe, 5.80 wt % Mo, 269 ppm B, and Mo/Fe=1.57. This aged catalyst
was used to oxidize the thermodynamic distribution of xylene isomer
mixture, p-xylene, m-xylene, and o-xylene.
Aged catalyst, 0.335 g (1.0 mL), was loaded into a micro-reactor equipped
with an on-line GC. Catalyst was pre-calcined in situ at 700.degree. C.
for 2 hours. A 10 mL syringe was filled with the xylene isomer mixture and
was calibrated on the syringe pump at 0.1286 g/hr. WHSV for mixed xylene
and p-xylene alone were, respectively, 0.38 L/hr and 0.09 L/hr. By means
of a Brook mass flow controller 400 sccm of gas (2 vol % O.sub.2, 2 vol %
N.sub.2, and balance He) was passed over the catalyst to give a contact
time of 0.14 sec. Molar ratio of O.sub.2 /xylenes was 18 and of O.sub.2
/p-xylene was 71. A Supelco Wax capillary column was used to analyze the
xylene isomers. Conversion and selectivity were based on the detected
products. Reaction conditions were as follows.
PX:MX:OX=1:2:1,
Catalyst loading: 0.335 g (1.0 mL),
O.sub.2 /xylene=18/1,
Flow rate: 400 sccm/min,
Contact time: 0.14 sec,
Total xylene pump rate (WHSV): 0.38 g/hr,
p-xylene pump rate (WHSV): 0.09 g/hr.
Results showed that p-xylene was preferentially oxidized at 400.degree. C.
in a mixed xylene stream at p-xylene conversion of 45%, while leaving
other isomer intact. Selectivity of COx was 17% (based on p-xylene mol %),
35 mol % TAL selectivity, and 48 mol % TPAL selectivity. Results are shown
in Table 15 below.
TABLE 15
______________________________________
Oxidation of a Mixed Xylene Feed Over Fe--Mo--DBH
Temperature, .degree.C.
325 350 375 400 425 450 475
______________________________________
Total xylene cov.,
2 4 8 13 21 28 35
mol %
p-Xylene conv.,
7 15 29 46 64 80 92
mol %
selectivity based on C.sub.8 mol %
Carbon oxides
1 14 15 17 18 21 25
Benzaldehyde
0 0 0 0 2 2 2
m,o-Tolualdehyde
0 0 0 0 4 7 14
TAL 52 43 39 35 28 22 18
TPAL 47 44 46 48 48 48 41
______________________________________
EXAMPLE 22
The Fe-Mo-DBH catalyst used in Example 21 was again used in oxidation of a
mixed xylene feed under the identical conditions employed in Run 6 except
the feed also contained ethylbenzene in molar ratio of
ethylbenzene:p-xylene:m-xylene:o-xylene=2:5:10:5, which is a composition
typical of commercially available streams. Results shown in the following
table demonstrate that a substantial portion of the ethylbenzene was
converted along with p-xylene at reaction temperatures above 400.degree.
C. Styrene which was expected to be form by oxidation of ethylbenzene via
dehydrogenation under these conditions, was, however, not detected.
Results are shown in Table 16 below.
TABLE 16
______________________________________
Oxidation of a Mixed Xylene Feed Containing
Ethylbenxend Over Fe--Mo--DBH
Temperature, .degree.C.
350 375 400 425 450
______________________________________
p-Xylene conv.,
11 26 51 80 95
mol %
Ethylbenzene conv.,
0 4 12 25 42
mol %
m-Xylene conv.,
0 1 2 5 10
mol %
o-Xylene conv.,
0 0 2 7 12
mol %
selectivity based on C.sub.8 mol %
Carbon oxides
25 31 31 28 31
Benzaldehyde 0 0 4 4 5
m, o-Tolualdehyde
0 0 0 4 8
TAL 37 32 28 22 16
TPAL 39 37 39 41 41
______________________________________
EXAMPLE 23
For this Example Fe-Mo-DBH catalyst used in Example 22 was coated with
tetramethylorthosilicate in the reactor. Fe-Mo-DBH catalyst was calcined
at 500.degree. C. for 2 hours and allowed to cool to 175.degree. C.
Tetramethylorthosilicate vapor was carried by nitrogen into the reactor at
ambient temperature for 45 min. Then the reactor was heated under nitrogen
to 360.degree. C., nitrogen replaced with 160 sccm of air, and kept at
450.degree. C. overnight. This procedure was repeated. Total amount of
tetramethylorthosilicate passed through the reactor was estimated to be in
a large excess over the saturation point for the exterior sites of the
catalyst.
Oxidation of a mixed xylene feed containing ethylbenzene as employed in
Example 22 was carried out under reaction conditions used in Example 22.
Results, which are summarized in Table 17 below, demonstrate that silica
coated Fe-Mo-DBH catalyst was more effective in selective oxidation of
p-xylene from the xylene isomer mixture containing ethylbenzene.
TABLE 17
______________________________________
Oxidation of a Mixed Xylene Feed Containing
Ethylbenxend Over Si/Fe--Mo--DBH
Temperature, .degree.C.
350 375 400 425 450
______________________________________
p-Xylene conv.,
12 23 44 72 88
mol %
Ethylbenzene conv.,
2 3 4 14 31
mol %
m-Xylene conv.,
<1 <1 <1 <1 <1
mol %
o-Xylene conv.,
<1 <1 <1 <1 <1
mol %
selectivity based on C.sub.8 mol %
Carbon oxides
30 29 32 32 39
Benzaldehyde 2 3 4 14 31
m, o-Tolualdehyde
0 0 0 5 9
TAL 36 36 31 24 20
TPAL 34 36 33 34 26
______________________________________
EXAMPLE 24
Fe-Mo-DBH catalyst was made according to the procedure set out in Example 8
and when analyzed contained 9.1 wt % Mo and 2.37 wt % Fe (Mo/Fe=2.2).
Fe-Mo-DBH catalyst (1.4 mL, 0.5 g) was loaded into a quartz microreactor
and tested in p-xylene conversion for TPAA and TAL yield with a feed
admixed with He and CO.sub.2. Results at 325.degree. C. showed that in He
p-xylene conversion was 37.7% with 47.5 mol % TAL selectivity, 42.0 mol %
TPAA selectivity, and selectivity to benzaldehyde of 3.4 mol %, but in
CO.sub.2, conversion of p-xylene was 61.6% with 41.8 mol % TAL
selectivity, 40.0 mol % TPAA selectivity, and selectivity to benzaldehyde
was 3.0mol %. Results are shown in Table 18 below.
TABLE 18
______________________________________
PX Oxidation With He or CO.sub.2 Over Fe--Mo--DBH
Temp. PX Conv..sup.1
PX Conv..sup.2
(.degree.C.) (%) (%)
______________________________________
250 6.9 18.2
275 12.5 25.6
300 22.1 40.2
325 37.7 61.6
350 57.0 82.5
375 77.3 95.6
400 93.3 99.0
______________________________________
.sup.1 0.1 vol % PX, 1.0 vol % O.sub.2, 1.0 vol % N.sub.2 in He
.sup.2 0.1 vol % PX, 1.0 vol % O.sub.2, 1.0 vol % N.sub.2 in CO.sub.2
EXAMPLE 25
Fe-Mo-DBH catalyst was made according to the procedure set out in Example 8
and contained 6.8 wt % Mo, 1.88 wt % Fe, and 0.05 wt % B (Mo/Fe=2.2).
About 1.4 mL (0.5 g) of Fe-Mo-DBH catalyst was loaded into a quartz
microreactor and tested in p-xylene conversion for TPAA and TAL yield with
a feed admixed with He and CO.sub.2. Results at 350.degree. C. showed that
in He p-xylene conversion was 41.2% with 50.2 mol % TAL selectivity, 23.5
mol % TPAA selectivity, selectivity to benzaldehyde of 2.4 mol %, and
selectivity to maleic anhydride of 2.4 mol %, but in CO.sub.2 conversion
of p-xylene was 65.5% with 9.1 mol % TAL selectivity, 11.1 mol % TPAA
selectivity, selectivity to benzaldehyde of 2.7 mol %, and selectivity to
maleic anhydride was increased to 6.0 mol %. Results are shown in Table 19
below.
TABLE 19
______________________________________
PX Oxidation With He or CO.sub.2 Over Fe--Mo--DBH
Temp. PX Conv..sup.1
PX Conv..sup.2
(.degree.C.) (%) (%)
______________________________________
250 8.6 23.4
275 11.1
300 17.6 33.3
325 28.3
350 41.2 65.5
375 60.7 84.1
400 81.5 96.3
425 96.3
______________________________________
.sup.1 0.1 vol % PX, 1.0 vol % O.sub.2, 1.0 vol % N.sub.2 in He
.sup.2 0.1 vol % PX, 1.0 vol % O.sub.2, 1.0 vol % N.sub.2 in CO.sub.2
EXAMPLE 26
Example 25 was repeated with a Fe-Mo-DBH composition made according to the
procedure of Example 8 containing 6.8% wt % Mo and 1.85 wt % Fe
(Mo/Fe=2.15). Results are shown in Table 20 below.
TABLE 20
______________________________________
PX Conversions and Aldehyde Yield Ratios
For Different CO.sub.2 Levels.sup.1
PTAA + TAA
Temp. Conv. Ratio MA.sup.2 Yield Ratio
Yield Ratio
.degree.C.
CO.sub.2 /He
CO.sub.2 /He CO.sub.2 /He
______________________________________
300 33/13 0/0 28/12
350 66/40 6/2 55/37
375 84/59 15/6 64/53
400 96/82 28/11 60/68
______________________________________
.sup.1 0.1 vol % PX, 1.0 vol % O.sub.2, 1.0 vol % N.sub.2 in He or
CO.sub.2
.sup.2 MA is maleic anhydride
COMPARATIVE EXAMPLE 27
An aluminosilicate with the MFI structure having a Si/Al ratio of 30/1 was
made using 6. Kg H.sub.2 O, 570 g NaOH, 320 g NaAlO.sub.2
.multidot.3H.sub.2 O.multidot.0.11NaOH, 8.955 Kg of 35%
tetrapropylammonium bromide, and 14.548 g of Ludox AS-40 (40% silica).
Reactants were placed in a 10 gal autoclave and heated at 152.degree. C.
for 120 hr. The aluminosilicate was ammonium exchanged with NH.sub.4
NO.sub.3 solution filtered, dried at 120.degree. C. overnight, and
calcined at 538.degree. C. for 3 hr. The product contained 1.13% Al. The
sieve was treated first with FeCl.sub.3 at about 415.degree. C., washed
and dried, and the result treated with MoO.sub.2 Cl.sub.2 at about
300.degree. C. It was again washed and dried to give a product containing
about 2.21 wt % Fe and 5.3 wt % Mo (Mo/Fe=1.4). Results over this Fe/Mo
Aluminosilicate to catalyze the oxidation of PX are shown below in Table
21. The catlyst was then treated with additional MoO.sub.2 Cl.sub.2 and
MoO.sub.3 to increase the atomic ratio to a level of Mo/Fe=2.0, and testes
again for oxidation of PX under the same conditions of reaction. Results
were essentially identical to those shown below in Table 21.
TABLE 21
______________________________________
PX Oxidation Over Fe/Mo Aluminosilicate
(ZSM-5 Type) Catalyst
Temp. PX Conv. Selectivities.sup.3, %
.degree.C.
% Tol.sup.1
PSC.sup.2
p-TAL.sup.4
CO.sub.x
______________________________________
250 18 74 23.8 * 3.7
300 25 60 17 * 22.2
350 56 66 3.8 * 21.0
400 95 36 0.3 * 42.6
______________________________________
.sup.1 Tol is toluene
.sup.2 PSC is pseudocumene
.sup.3 No TPAA was found
.sup.4 Less than 1%
COMPARATIVE EXAMPLE 28
A portion (100 g) of Silicalite S-115 (Union Carbide) was steamed and
heated at a rate of 5.degree. C. per rain to 650.degree. C. and then held
at 650.degree. C. for 1 day. The temperature was then raised while
steaming at 5.degree. C. to 800.degree. C. and held there for 6.9 days.
After calcining 97.2 g were recovered. The sample was then heated with
SOCl.sub.2 vapor to remove aluminum. The resulting solid was first treated
with FeCl.sub.3 vapor and then MoCl.sub.5 vapor. ICP analysis give 5.8 wt
% Mo and 1.3 wt % Fe (Mo/Fe=2.6). A feed of 0.1 vol. % p-xylene, 1.0 vol %
O.sub.2, 2.0 vol. % N.sub.2 in He was oxidized over the Fe/Mo Silicalite
with the results shown below in Table 22.
TABLE 22
______________________________________
Fe/Mo/Silicalite Oxidation of PX
Selectivities, %
Temp., .degree.C.
PX Conv., %
PTAA TAL CO.sub.x
______________________________________
300 <1 0 24.8 68.4
350 1.6 6.6 27.0 61.5
400 5.7 8.4 21.1 72.8
450 17.5 14.1 20.4 61.5
500 40.5 27.2 21.6 45.4
550 65.5 33.4 18.5 39.8
______________________________________
EXAMPLE 29
Fe-Mo-DBH catalyst employed in Example 10 (Mo/Fe=1.8) was tested in a gas
phase O.sub.2 -oxidation of pseudocumene. Catalyst (0.504 g, 1.4 mL), was
loaded into a quartz reactor equipped with an on-line GC, and the
oxidation of pseudocumene was carried with a premixed gas containing 4.0
vol % O.sub.2, and 4.0 vol % N.sub.2 in He. The effluent product stream
was analyzed by GC. In a typical run at 450.degree. C., pseudocumene was
converted to methylterephthaldehyde (47.9 mol % selectivity),
3,4-dimethylbenzaldehyde (11.7 mol % selectivity),
2,5-dimethylbenzaldehyde (9.7 mol % selectivity), 2,4-dimethylbenzaldehyde
(8.2 mol % selectivity) and COx (19.5 mol % selectivity) at 27.5 mol %
conversion of pseudocumene.
EXAMPALE 30
The Sb-Mo-DBH catalyst used in Example 13 was also used for a gas phase
O.sub.2 -oxidation of pseudocumene. Catalyst (0.499 g, 1.4 mL), was loaded
into a quartz reactor, and the oxidation of pseudocumene was carried out
by feeding a premixed gas containing 4.0 vol % O.sub.2 and 4.0 vol %
N.sub.2 in He at 550.degree. C. The effluent product stream was analyzed
by GC giving selectivities to methylterephthaldehyde,
3,4-dimethylbenzaldehyde, 2,4-dimethylbenzaldehyde,
2,5-dimethylbenzaldehyde and COx of, respectively, 37.1 mol %, 17.0 mol %,
12.6 mol % 15.1 mol %, and 18.2 mol %, at a pseudocumene conversion of
14.1 mol %
EXAMPLE 31
Durene was dissolved in benzene to give a molar ratio of benzene/durene of
2.2. The solution was pumped into the micro-reactor and loaded with 0.50 g
of the same Fe-Mo-DBH catalyst used in Example 29 and oxidized in a flow
of premixed gas consisting of 6 vol % O.sub.2 and 6 vol % N.sub.2 in He at
two different temperatures, 425.degree. C. and 450.degree. C. Product
effluent was analyzed by GC, and each product identified with GC/MS.
Results are summarized in Table 23 below
TABLE 23
______________________________________
Oxidation of Durene Over Fe--Mo--DBH Catalyst
Temp. .degree.C.
A.sup.1 B.sup.2
C.sup.3 D.sup.4
E.sup.5
______________________________________
425 6.3 1.1 1.4 3.1 2.6
450 35.6 6.7 7.4 8.2 8.1
______________________________________
.sup.1 2,5dimethylterephthaldehyde
.sup.2 2,3dimethylphthalic anhydride
.sup.3 2,3dimethylphthaldehyde
.sup.4 2,4,5trimethylbenzaldehyde
.sup.5 Maleic anhydride
EXAMPLE 32
A amount of 2,6-dimethylnaphthalene was dissolved in benzene to give a
solution containing a molar ratio of benzene to 2,6-dimethylnaphthalene of
seven. This solution was pumped into the micro-reactor loaded with 0.52 g
of the Fe-Mo-DBH catalyst employed in Example 31 and oxidized in a stream
of 6 vol % O.sub.2 and 6 vol % N.sub.2 in He at 400.degree. C. Reactor
effluent, excluding CO.sub.2, was analyzed by GC and GC-MS which
identified as the sole organic product 2-methyl-6-formylnaphthalene, a
monoaldehyde product. The amount of monoaldehyde product was 14 area % in
86 area % of 2,6-dimethylnaphthalene using a FID on the GC.
EXAMPLE 33
The Fe-Mo-DBH catalyst used in Example 318 was employed for oxidation of
4,4'-dimethyldiphenyl. 4,4'-dimethyldiphenyl was dissolved in benzene to
give a molar ratio of benzene to substrate equal to 16. The resulting
solution was pumped into the micro-reactor and the substrate was oxidized
in a flow of 6 vol % O.sub.2 and 6 vol % N.sub.2 in He at 350.degree. C.
Analysis of the product effluent by GC and GC/MS showed that it consisted
of 20 area % of 4-methyl-4'-formyldiphenyl, a monoaldehyde product, and 80
area % of starting material using a FID on the GC. Carbon dioxide was not
determined.
COMPARATIVE EXAMPLE 34
A physical mixture was prepared using 0.5 g of Fe.sub.2 (MoO.sub.4).sub.3
and 5.0 g of HAMS-1B sieve (1.09 wt % B) and 0.5 g of the mixture loaded
in a micro-reactor. A O.sub.2 /PX mixture (10/1) was fed to reactor with
results as shown in Table 24 below.
TABLE 24
______________________________________
PX Oxidation Over a Physical Mixture of
Fe.sub.2 (MoO.sub.4).sub.3 and HAMS-1B Sieve
Temp., .degree.C.
300 350 400 450 500
______________________________________
PX Conv., %
0 2.6 8.2 22.4 46.6
Selectivities, %
Toluene 60.2 51.9 39.1 30.6
Benzaldehyde 0 3.2 4.4 6.7
Pseudocumene 5.3 2.2 0.7 0.4
Trimethylbi- 17.9 7.6 1.6 0.2
phenylmethane
TAL 23.5 23 18.1 12.1
TPAA 0 2.2 3.0 4.0
CO 0 16.4 20.1 21.1
CO.sub.2 0 0 10.6 20.7
______________________________________
COMPARATIVE EXAMPLE 35
A sample of Fe.sub.2 (MoO.sub.4).sub.3 containing 10 wt % MoO.sub.3, was
used to oxidize a 10/1 mixture of O.sub.2 /PX under the conditions of
Example 10. No conversion was found at temperatures below about
400.degree. C. At 450.degree. C. a p-xylene conversion of 9% was obtained
with selectivities to TPAA, TAL and CO.sub.2 of, respectively, 24%, 59%,
and 18%.
EXAMPLE 36
Fe-Mo-DBH catalyst was made by the method of Example 2 and this catalyst
contained 6.2 wt % Mo, 1.86 wt % Fe, and 0.109 wt % B. (Mo/Fe=1.94). A 10
g sample of this Fe-Mo-DBH catalyst was used for PX oxidation
intermittently for 50 hr in a study of process conditions. PX oxidation
was then continued using 2 g PX/hr, 2 L/min of air, 4 L/min of nitrogen
with a WHSV of 0.20 hr.sup.-1, contact time 0.28 sec, and 350.degree. C.
temperature. Results are shown in Table 25 below. Analysis of the catalyst
after 200 hr use give 6.3 wt % Mo and 1.79 wt % Fe (Mo/Fe=2.05).
TABLE 25
______________________________________
PX Oxidation Catalyst Lifetime Study of Fe--Mo--BDH
Hours.sup.1
1 10 25 50 76 86 99
______________________________________
PX Conv., %
36.8 37.3 38.5 36.4 32.1 33.2 31.4
MA 6.1 6.9 6.4 5.7 5.9 6.2 5.7
TAL 31.7 37.2 37.9 38.7 39.3 38.4 40.4
TPAA 39.8 28.8 28.2 25.9 25.5 26.2 24.3
TA.sup.2 4.4 4.7 5.1 5.3 5.3 5.8 5.3
CO.sub.x 14.6 19.3 19.5 21.9 21.2 20.7 21.5
______________________________________
.sup.1 Time on stream plus 50 hr
.sup.2 ptoluic acid
EXAMPLE 37
Fe-Mo-DBH catalyst was prepared by the method of Example 2 and when
analyzed contained 4.6 wt % Mo and 1.41 wt % Fe (Mo/Fe=1.92). A mixture of
benzene and N.sub.2 was passed over the sample in a reactor at
temperatures of 350.degree. C. to 410.degree. C. and the oxidation
products analyzed. At 350.degree. C. the product effluent contained 92 wt
% benzene and 8 wt % phenol. At 410.degree. C. the content was 83 wt %
benzene and 16 wt % phenol.
EXAMPLE 38
The Fe-Mo-DBH catalyst composition used in Example 29 was used to
oxidatively dehydrogenate ethylbenzene, p-diethylbenzene and
t-butylethylbenzene. Results are shown in Table 26.
TABLE 26
__________________________________________________________________________
Oxidative Dehydrogenation of
Alkylbenzenes Over Fe--Mo--DBH
__________________________________________________________________________
Compound
Temp. .degree.C.
Conv. %
Selectivities, %
__________________________________________________________________________
p-DVB.sup.4
VEB.sup.5
TPAA
p-DEEB.sup.1
325 75 90
Benzald
MA Styrene
COx
EB.sup.2
325 5.2 37.9 0 25.3 36.8
350 10.3 33.6 21 14.2 31.1
TBS.sup.6
Cracked Pdts.
TBEB.sup.3
400 4.7 60 4
450 11.8 60 3
500 13.0 68 7
__________________________________________________________________________
.sup.1 pdiethylethylbenzene
.sup.2 ethylbenzene
.sup.3 tbutylethylbenzene
.sup.4 pdivinylbenzene
.sup.5 vinylethylbenzene
.sup.6 tbutylstyrene
EXAMPLE 39
A co-formed Mo/Fe/SiO.sub.2 catalyst was prepared by adding two aqueous
solutions, ammoniumparamolybdate and ferric nitrate, simultaneously to
Nalco silica gel 1034A under vigorous agitation at ambient temperature
over a period of 3 hr. This mixture was allowed to react under agitation
at 800.degree. C. for another a few hours Resulting gel was kept at
ambient temperature overnight. Water was removed from the gel by a rotary
evaporator, dried in a vacuum oven, sieved to 20-40 mesh size, and
calcined at 600.degree. C. for 5 hrs. Calcined catalyst (12-16 g), 20-40
mesh size, was loaded into a quartz reactor. Feeds consisting of an
aqueous solution of nitric acid (30%) and benzene were separately pumped.
Nitrogen gas flow was regulated with a micrometering valve and measured by
a gas bubble meter. Reactor effluent was cooled in a water condenser and
then collected, typically, in a series of traps chilled with water/ice and
dry ice/acetone. Nitrogen dioxide, a decomposition product of nitric acid,
was purged by a carrier gas, nitrogen. Testing conditions, described
below, were closely followed throughout this work.
Catalyst loading: 15-20 mL (12-16 g)
LVHSV of benzene: 0.1 hr.sup.-1
Molar ratio of nitric acid/benzene: 2:1
Flow of nitrogen: 20-50 mL/min
Reactants and products were identified and quantified by GC analysis on
Shimadzu GC-9A fitted with a "Fused Silica" capillary column, 50 meter 007
FFAP, 0.25 mm I.D., 0.25 mm film thickness, Quadrex Corporation. Products
were identified by GC and GC/MS spectroscopy. Typical results in a series
of continuous run were listed in Table 26 below. The catalyst was still
active even after a prolonged continuous run, longer than two months.
TABLE 26
______________________________________
One-step Hydroxylation of Benzene to Phenol
Gas Phase Nitric Acid Oxidation
______________________________________
Run no. 1 2 3
Temperature, .degree.C.
370 450 475
Reaction Product Distribution wt %
Benzene 43.88 56.89 59.30
Nitrobenzene
56.12 0.00 0.00
Phenol 0.00 41.00 38.89
Unidentified
0.00 2.11 1.81
Recovery* 72 67-75 76
______________________________________
*Theoretical recovery is 77-82% depending on the conversion level
EXAMPLE 40
In this Example a Fe-Mo-DBH catalyst was used for conversion of butane.
Fe-Mo-DBH catalyst containing 8.70 wt % Mo and 1.08 wt % Fe was prepared
from FeCl.sub.3 and MoO.sub.2 Cl.sub.2 according to the CVD technique and
calcined at 650.degree. C. for 8 hrs. Calcined catalyst contained 7.0 wt %
Mo and 1.15 wt % Fe (Mo/Fe=3.5). Calcined catalyst (10 g, 28 mL), was
loaded into a quartz reactor equipped with an on-line GC, and the
oxidation of n-butane was carried out with air. Feed gas composition was
0.5 vol % n-butane in air (4.5 sccm n-butane and 792 sccm air).
Conditions, described below, were closely followed throughout this work.
O.sub.2 /n-butane: 48
Flow rate: 795.0 sccm
WHSV: 0.103 hr.sup.-1
Contact time: 2.113 sec.
TABLE 27
______________________________________
Conversion of Butant over Fe--Mo--DBH
Temperature, .degree.C.
350 375 400 425
______________________________________
n-butane conv., %
3.4 4.8 7.1 11.3
selectivity based on butane mol %
Maleic anhydride
22.3 14.6 12.1 11.2
Carbon monoxide
49.7 40.1 43.6 50.0
Carbon dioxide
27.9 34/8 45.4 42.2
______________________________________
EXAMPLE 41
In this Example a Fe-Mo-DBH catalyst was used for conversion of
p-methylanisole. The Fe-Mo-DBH catalyst employed in Example 3 (0.52 g) was
loaded into the micro-reactor equipped with an on-line GC, and heated to
300.degree. C. under a flow of 6% O.sub.2 in He (50 mL/min). Once the
reactor reached to 300.degree. C., p-methylanisole was introduced into the
reactor by a syringe pump at a rate of 0.2 g/hr. Oxidation of
p-methylanisole was carried out under conditions used in Example 3.
Results show that selectivity of p-anisaldehyde and CO.sub.2 were,
respectively, 81% and 15% at p-methylanisole conversion of 27%. Both
conversion and selectivity were calculated based on the area of GC peaks.
EXAMPLE 42
In this Example a Fe-Mo-DBH catalyst was used for conversion of
4-ethyltoluene. A Fe-Mo-DBH catalyst containing 5.6 wt % Mo,. 1.16 wt % Fe
and 720 ppm B (Mo/Fe=1.76), was prepared by the chemical vapor deposition
method. Catalyst calcined at 650.degree. C. was loaded into a quartz
reactor, and oxidation of 4-ethyltoluene was carried out using two gas
streams consisting of 0.16 vol % ethylbenzene (3.5 g/hr), 5.5 vol %
O.sub.2, and 20 vol % N.sub.2 in either He or CO.sub.2 at temperature
varying from 350.degree. C. to 400.degree. C. Reactor effluent was
analyzed by GC attached to the reactor and products were analyzed by means
of GC/MS. Results in He at 375.degree. C. showed that 4-ethyltoluene
conversion was 39% with 17.2 mol % TAL selectivity, and 23 mol %
selectivity to p-toluic acid, but in CO.sub.2, conversion of
4-ethyltoluene was 69.9% with 20 mol % TAL selectivity and selectivity to
p-toluic acid was increased to 34.8 mol %.
EXAMPLES 43 AND 44
Fe-Mo-DBH was made according to the CVD procedure of Example 2. It was
analyzed and contained 2.57 wt % Fe 7.7 wt % Mo, and 660 ppm B (Mo/Fe=2.3)
and surface area of 245 m.sup.2 /g. Fe-Mo-DBH catalyst (10 g) was tested
at varying temperatures for oxidation of styrene; first in a stream of
0.15 vol % styrene, 4.2 vol % O.sub.2, 15.4 vol % N.sub.2, and balance He;
and then under the same conditions in a stream of 0.16 vol % styrene, 5.0
vol % O.sub.2, 18.5 vol % N.sub.2, and balance CO.sub.2. Results are
shown, respectively, in Table 28 and Table 29 below.
TABLE 28
______________________________________
Oxidation of Styrene Over Fe--Mo--DBH with O.sub.2 in He
Temp., .degree.C.
275 300 325 350
______________________________________
Styrene Conv., %
20.8 42.8 71.0 94.5
Selectivities, %
Benzoic acid 49.3 51.2 56.5 43.5
Benzaldehyde 21.6 21.3 19.0 19.0
PNAA.sup.1 4.6 2.5 1.0 0.2
PCPN.sup.2 7.4 6.4 3.4 1.1
MAN.sup.3 1.5 1.9 3.3 11.1
CO 6.5 7.4 6.9 9.6
CO.sub.2 9.1 9.4 9.7 15.5
______________________________________
.sup.1 PNAA is phenylacetaldehyde
.sup.2 PCPN is acetophenon
.sup.3 MAN is maleic anhydride
TABLE 29
______________________________________
Oxidation of Styrene Over Fe--Mo--DBH with O.sub.2 in CO.sub.2
Temp., .degree.C.
250 275 300 325 350
______________________________________
Styrene Conv., %
6.2 16.0 31.0 50.6 90.4
Selectivities, %
Benzoic acid
42.6 51.3 59.4 63.7 62.2
Benzaldehyde
33.6 26.5 22.7 21.0 21.4
PNAA.sup.1 10.6 5.7 3.1 1.5 0.4
PCPN.sup.2 13.3 10.4 7.3 4.3 1.8
MAN.sup.3 0 0 1.8 2.8 7.3
CO 0 6.1 5.8 6.6 6.6
______________________________________
.sup.1 PNAA is phenylacetaldehyde
.sup.2 PCPN is acetophenon
.sup.3 MAN is maleic anhydride
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